Hi TK.
Tyres is an interesting one.
Everyone is going to have their preferences to that one, and I think that there are also two other very important factors. The first is very much a mental one. If you believe that X tyre is better than Z, then the chances are that you are going to ride better on X than Z, possibly even if the complete opposite were true.
Next up is tyre pressures. Last Saturday I watched someone slipping and sliding across off camber tree roots, and yet only days before, I had ridden over almost identical terrain, almost identical conditions, and on exactly the same tyres, with not a single slide. After talking to the guy, the difference came down to tyre pressure. He was running the tyres way to high.
I would have bought Pannaracer Fire Pros, had it not been for cost. I researched tyres pretty thoroughly, and on paper there wasn't enough difference to justify me spending over double the cost of the WTB's.
It is too soon to say how things stack up to compare the two, but I have to say that I really loved the experience on them last Saturday. They didn't roll as well on the road, sounded like an old Landrover using Firestone SAT tyres, and the first initial session on the road, produced a definite rumble feeling through the handlebars. They were also the hardest tyre to fit, that I have ever come across. Usually I never need tyres, but these really tested my tyre levers and saw the levers pretty much bent backwards.
The offroad capabilities were superb, although I did drift very wide a couple of times. This was down to nothing more than my own 'mental' approach, and being wary of them. I needn't had worried though, as the capabilities of the tyres, easily out performs that of my own ability.
They grip like crazy, and I cannot speak highly enough of how they handled sketchy terrain and roots. I did receive comments about the amount of crud that I was throwing up though.
The bike came fitted with Schwalbe Rocket Ron's, and if I were to recommend a tyre for your use, I think that these would be perfect. I'm guessing that your bike already has either these, or Racing Ralphs. The Ralphs are also a superb tyres, but the limitations are quite obvious when it comes to muddy terrain. The only negative thing that I could say about either of the Schwalbe choices, is that they aren't very puncture resistant. I guess that being such light weight tyres, this aspect is always going to be a compromise.
I'll have to have a think about your second question. It's not really a particularly easy one to answer.